Production of flavanthrone dyestuff intermediates



Patented Dec. 6, 1932 UNITED STATES PATENT OFFICE WILLIAM SMITH AND JOHN THOMAS, OF GEANGEMOUTI-I, SCOTLAND, ASSIGNORS TO SCOTTISH DYES, LIMITED, OF GRANGEMOUTH, SCOTLAND PRODUCTION OF FLAVANTHBONE DYESTUFF INTERIVIEDIATE-S 7 N0 Drawing. Application filed March 31, 1928, Serial No. 266,452, and in Great Britain May 26, 1926.

This invention relates to the production of fiavanthrone dyestufi intermediates.

As a result of researches, we have found among other things that if anthraquinone derivatives, particularly 1-halogen -amino derivatives are converted into 1-halogen-2- urethane derivatives they may then be trans terred smoothly into the corresponding flavanthrone type products.

Ve have also found that if the conditions for the condensation of two molecules of 1-halogen-2-urethane-anthraquinone derivatives are less drastic, a product is formed which we regard as 1: 1-dianthraquinonyl- 2:2-diurethane derivative. Dianthraquinonyl bodies or this character furnish valuable dyestuff intermediate products and usually may be readily purified and smoothly converted by a variety of methods into fiavanthrone derivatives.

The invention in brief consists in a process for the formation of 1: 1-dianthraquinonyl- 2 2-diurethane derivatives by the condensation of two molecules of 1-halogen-2- urethane-anthraquinone derivatives.

The invention includes the extraction or purification of dianthraquinonyl-diurethane condensation products prepared as indicated above by means of organic solvents, for example mono-chlor-benzol.

The invention includes a modified method of working up the reaction mixture, filtration of the mixture whilst hot, whereby the 1 1- dianthraquinonyl 2 2- diurethane derivatives may be separated by reason of their solubility in the hot solvent.

The invention also consists in processes and products substantially as herein described.

The following examples illustrate how the invention may be carried into eiiect, all parts being parts by weight Example 1 According to this example 20 parts of ethyl urethane prepared from 1-chl0r-2-amino-anthraquinone and ethyl chloro-formate are suspended m 80 parts of n1tro-benzene and 8 parts of copper powder are added to the mixture. The contents are well stirred and the melt heated at 160 for several hours.

At the end of this time the mixture is cooled down and filtered. There is thus obtained product in crude or impure form having the structural formula 1: 1-dianthraquinonyl- 2 2-diurethane, this crude product containing copper and any fiavanthrone that has been formed. The probable course of the reaction is the conversion of the 1-chlor-2amino-anthraquinone into. anthraquinone-lchlor-2ethyl-urethane, two molecules of which combine with one molecule or" copper to form one molecule of 1: 1-dianthraquinonyl-2:2"-diethyl urethane and one molecule of cupric chloride.

This 1 1-dianthraquinonyl 2 2 diure thane is readily extracted from this crude product by treatment with an organic solvent, for example mono-chlorbenzol, from which it crystallizes on concentration in magnificent glistening yellow plates which melt above 250 C.

EwampZe 2 An alternative method of working up the reaction mixture is to filter at about 160 (3.,

after the reaction is completed. There is thus left behind on the filter apparently any flavanthrone that may have been formed, as well as the unchanged copper and salts of copper. The filtrate, on cooling, deposits the aforesaid 1: 1-dianthraquinonyl-2 2-diuretha-ne in a purified form.

General Modifications may be made in the processes described above; for instance urethanes other than those mentioned may be employed, for example those obtained by the action of butylcl lor-formate v or phenyl-chlor-iormate on l-chlor-Q-amino-anthraquinone. The product in the first case is anthraquinone-l-chlor- Q-butyl-urethane which, used as a starting material, yields 1: 1-dianthraquinonyl-2 2- dibutyl urethane, and in the case of the phenyl body, the product is anthraquinone-l-chlor-2- phenyl urethane which yields 1: 1-dianthraquinonyl-2:2-diphenyl urethane. Instead of 1-chlor-2-amino-anthraquinone, the corresponding'brom derivative can be used. The two corresponding derivatives obtained from the brom-body are respectively anthraquinone-1-bromo-2-buty1 urethane and anthra quinone-l-brmo-2-phenyl urethane, these yielding dibutyl urethane and 1: 1-dianthraquinonyl-2 2-1 1-dianthraquinonyl 2 2- diphenyl urethane respectively. Other derivatives and higher. halogenated amino-chloranthraqulnones contammg the grouping 1- halogen-2am1no-anthraquinone can be used v for example 1-3-dibrom-2-amino-anthraquin one. In this case, the butyl and phenyl products are anthraquinone-l g-dibrom-Q-butyl urethane, and anthraquinone-l'z 8-dibrom-2- phenyl urethane, which yield respectively 1 :1"-di anthraquinonyl-3 :3 -dibrom 2 :2 dibutylurethane, and 1 :'1'-dianthraquinonyl 3: 3'-dibrom-2 2-diphenyl urethane;

-The condensation can becarried outin other media besides nitrobenzene for example naphthalene as indicated above and in some cases the reaction can be caused to proceed by .dry baking for example in the manner described.

.Dianthraquinonyl-diurethane prepared as I described above usually dissolves in alkaline hydrosulphite with a red vat but this vat does not dye cotton and the colour of this vat distinguishes it from fia-vanthrone which gives royal blue vat.

Various 1-halogen-2-amino-anthraquinone v derivatives referred to above may be treated according to the present invention by processes such as those indicated.

The conversion of I-halOgen-Q-urethane a-nthraquinone derivatives to fiavanthrone may be effected directly at a high temperature in an inert solvent in the presence of a finely divided metal such as copper, orv the 4. The process which consists in heating anthraquinone-1-halogen-2-urethanes .with

.metallic copper at a temperature between about 135 C. and 175 C.

5. A process which consists in heating anthraquinone-l-halogen-2 urethanes with metallic copper in the presence of an inert organic medium at a temperature of between about 135 C. to 175 C.

6. A process for the formation of flavanthrone dyestufi intermediates which consists in condensing two molecules of anthraquinone-1-halogen-2-urethanes in the presence of .metallic copper and of an inert aromatic solvent of high boiling point at a temperature of between about 135 C.-to about 175 C,

In testimony whereof we have signed our names to this specification. I V

WILLIAM SMITH.

JOHN THOMAS.

process may be carried out in two stages as indicated above when the process is stopped at a point where the 1: 1-dianthraquinonyl- 2 2-diurethane derivative has. been prepared. This derivative may then be purified, if necessary, and afterwards converted by the methods described to the fiavanthrone derivatives.

The 1: 1 dianthraquinonyl 2 2 diurethane derivativesmay be converted into the converted into flavanthrone derivatives in many ways.

What we claim is 1. 1: 1-'dianthraquinonyl-2: 2'-diurethane. 2. 1:1-dianthraquinonyl-2:2-diurethanes. 3. 1 :1 -dianthraquinonyl-2 :2-dialkyl-urethanes. a

fiavanthrone derivatives by any of the followa 

